Via a bulletin board post, a member of Capcom has confirmed that there are NO plans to bring Dead Rising and Lost Planet to the Wii or PS3 formats, meaning it will remain an Xbox 360 exclusive. This confirmation comes following the news that a number of Capcom titles are set to go multi-platform.
The answer is Dead Rising and Lost Planet are not slated to appear on Wii or PS3 as far as current plans go. The reasons for this are quite convoluted and I'm bound by NDAs on these matters so I can't divulge why this is the situation.
The quote delivered above references our strategy moving forward, not something that is necessarily retroactive. You can see evidence of this with our previously stated RE5 plans going to 360 and PS3 simultaneously.
Soruce: Capcom